The present invention is concerned with an aircraft panel structure and manufacturing method for the alleviation of stress. In particular, the following invention is concerned with an aircraft panel structure and manufacturing method for the alleviation of stress between two joined panels having different thermal expansion coefficients.
In aircraft design it is common to attach two panels having different thermal expansion coefficients. Such panels are often constructed from different materials such as composite and metal materials. If two such panels are joined at two discreet, spaced fastening points along their length, a decrease in temperature (as the aircraft ascends) will result in a different level of contraction between the fastening points for each material. This induces significant undesirable stresses in the materials and also in the fastening means (e.g. bolts).
Traditionally this problem has been alleviated with the use of clearance fixed bolts, however the use of such bolts reduces the joined components' resistance to fatigue and consequently the components have to be made larger and heavier in order to account for this reduction. This is undesirable.